Huperzine is a standardized extract from the Chinese club moss is an all-natural herbal supplement that may help prevent the breakdown of acetylcholine. Huperzine's action has been attributed to its ability to strongly inhibit acetylcholinesterase, the enzyme that breaks down acetylcholine in the synaptic cleft. Acetylcholine is involved in memory and learning. Huperzine A has also been found to be beneficial in patients with Alzheimer’s disease. Huperzine A had improvements in memory, cognition, and behavioral functions whereas only 36 percent of those on placebo improved. No severe side effects were found. Blood pressure, heart rate, electrocardiogram, electroencephalogram, liver and urine tests did not show any major abnormalities. The researchers say, "Huperzine A is a promising drug for symptomatic treatment of Alzheimer's disease."